In Japanese Patent Application Publication No. 10-41510 (JP-10-41510 A) (Patent Document 1), there is disclosed a semiconductor device that employs, as a temperature detection element, a PN diode that is arranged on a surface of a semiconductor substrate. A temperature of a surface of a semiconductor element is detected with the aid of a temperature dependency of a forward voltage of the PN diode that is arranged on the surface of the semiconductor substrate.